Symmetric and asymmetric stationarity tests of productivity

Studies of productivity in the operations and engineering management literature have typically focused on identifying the drivers of productivity and how best to manage resources. To date, the issues of the time-series behavior and the stochastic structure of productivity have largely been overlooked. This article examines the times-series properties of productivity utilizing several unit root and stationarity tests including one that allows for asymmetric adjustments to equilibrium. The findings suggest that productivity is a nonstationary process and first-differencing is necessary to render a stationary series. Moreover, we find some evidence of an asymmetric adjustment process in the productivity growth rates of manufacturing.